Aug. 4–Cerulean warblers have their own local magic. Besides the fact that cerulean is a cool word to say — and was even a theme for an “X-Files” episode — southeastern Pennsylvania and particularly the Schuylkill River have played roles in the cerulean warbler’s life history.

The first male cerulean warbler known to science was described in 1810 by the naturalist Alexander Wilson from a specimen shot in southeastern Pennsylvania. The first female cerulean known to science was collected along the Schuylkill River near Philadelphia in 1825.

Even more locally, Earl Poole found a pair of nesting cerulean warblers along the Hay Creek near Birdsboro on May 8, 1949 — the first recorded nesting in eastern Pennsylvania.

He followed the nesting activities and collected the empty nest for the Reading Public Museum natural history collection.

Cerulean warblers still nest along that stretch of the Hay Creek.

The bird, though, is listed as a species of special concern in Pennsylvania.

Ceruleans like large tracts of undisturbed forest near slopes or streams, and that habitat is in short supply these days.

The conservation of the Hopewell Big Woods area, which encompasses the Hay Creek watershed near the Birdsboro Reservoir, will go a long way in preserving that particular nesting area in southeastern Berks.

So it came as a rather pleasant surprise when Sue Schmoyer from Kutztown e-mailed that she, Catherine Elwell of District Township and Kerry Grim of Hamburg were keeping track of two pairs of cerulean warblers along the Bartram Trail between Port Clinton and Route 61: “I thought you might like to know that we have been able to confirm two cases of breeding cerulean warblers in Berks County. It seems that they really like the Bartram Trail between Route 61 and Port Clinton. Kerry Grim and I have been monitoring four different territorial males since May 5, and on Wednesday Catherine and I found one of the nests. Unfortunately, it contained a cowbird. It seems as if the parents know that the cowbird isn’t theirs, because when they bring food they seem to dig around till they can feed their own. … It’s amazing the number of cerulean warblers in that very short stretch of the trail. There’s indications that there may even be a fifth male around there, but the most we’ve heard or seen at any one trip is four. On the way in from the Kernsville desilting basin, we thought we heard another one before the railroad bridge, which would be a first for that location.”

The good news is that the ceruleans are nesting along the trail in northern Berks, but the bad news is the nest parasitism by cowbirds — one of the leading causes of cerulean warbler declines. Fragments in the forest will increase cowbird nest parasitism.

We can be a little more optimistic about the cerulean warbler’s status in the county.

Still more good news is the development of the Bartram Trail and other hiking opportunities in the city and county.

Just last week, city offi cials dedicated the new Angelica Park, and the week before that Michael DiBerardinis, secretary of the state Department of Conservation and Natural Resources, and members of the Berks County Conservancy toured the Angelica Creek Trail, which starts at the park and will eventually connect to the Nolde Forest Environmental Education Center.